The ultimate objective of the research projects in this program application is to improve our understanding of, and our therapeutic options in, chronic lymphocytic leukemia (CLL) through a coordinated investigation of the genetics, biochemistry, immunology and pharmacology of the disease and the associations between these biological parameters and clinical outcomes, including time from diagnosis to initial therapeutic intervention, response to therapy, time to progression, and overall survival. To achieve this, results of laboratory studies will be integrated into the clinical studies in a timely fashion. Important to the success of this project the collaboration with members of the Biostatistics core, who will provide assistance in the design and analysis of the clinical and laboratory research projects, as well as assist in designing the further exploration of promoting laboratory correlative findings in the CLL database assembled through this program project. The purpose of the Biostatistics Core (Core B) is to provide the following services that will be utilized by all the research projects. 1. To provide biostatistical collaboration for clinical research protocols. This includes all aspects of the design, conduct, analysis, and reporting of the clinical studies. 2. To provide biostatistical collaboration for all laboratory studies. This includes all aspects of the design, conduct, analysis, and reporting of such studies, including the coordination of laboratory results with parameters and outcomes from the clinical studies. 3. To advise on the database structure, to assure easy flow of data and into and out of the database analysis. 4. To assist in the supervision of data management, both at the central facility and at the institutional level, to maintain an accurate and complete computerized database. 5. To participate in the quality assurance of the data collected through an ongoing audit process. 6. To participate in the internal scientific review of projects proposed using the laboratory and clinical information contained in the database, as well as the tissue banking resources.